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Thesis Abstract – Banschbach (1986)

Title:

Bird Use of Lakes in the Claremont-Upland Area

Author and college:

Valerie Banschbach, Pomona College

Date:

May 2, 1986

Degree:

Bachelor of Arts in Biology

Advisor:

Larry Oglesby, Pomona College

Abstract:

I studied water bird use of two lakes in the Claremont-Upland area to determine what physical, chemical, and biological aspects of these lakes provide suitable water bird habitat and food resources. I censused the Bernard Field Station Lake in Claremont and a gravel pit freshwater area in Upland from 10/85 to 3/86 for water bird use. I also mapped theses sites, noted their water suface area and water depth changes, monitored their water chemistry, and censused their vegetation. The results of this work showed more total water birds per hour of observation time, and more birds per hour of observation time of each food preference type, at the Upland Lakes than at the BFS Lake, except for diving ducks, which I found at both sites in similar abundance, and coots, which I found at the BFS Lake in greater abundance than at the Upland Lakes. The Shannon-Weinger Index of Diversity, H´, used to determine bird species diversity, was higher for most individual census dates and on average, at the Upland Lakes than at the BFS Lake. The Upland Lakes had fewer species and less abundance of true aquatic plants han the BFS Lake; however, the BFS Lake had fewer different types of habitat (i.e., open shoreline, thick emergent shoreline vegetation, mudflats, grassy areas, etc.) than did the Upland Lakes. The Upland Lakes, although originally very similar to the BFS Lake in total water surface area, came to have four times the water surface area of the BFS Lake as time progressed, due to winter rainfall and run-off. The results of bird censuses also showed many more migrant than resident birds using the Upland Lakes area, while few migrant birds used the BFS Lake.

Water bird use differences between these sites are the result of the interaction of the unique ecological factors of each site. The Upland Lakes provide more diverse habitats, greater water surface area, a more accessible, open location for stopovers for migratory birds than the BFS Lake provides. The BFS Lake provides only two major habitat types for water bird use: thick shoreline emergent vegetation (mostly cattails), and open water. divind ducks and coots utilize these habitats well and thus, with the exception of migratory flocks of diving ducks, used the BFS Lake as frequently, or more frequently than they used the Upland Lakes. Other birds that forage in muddy, open shore or grassy, open shore area preferred the Upland Lakes area (dabbling ducks and shorebirds). Additional observation of similar water ara in Claremont, Upland, and Montclair, California could produce a large data base to demonstrate conclusively such tentative findings of this study as size of water surface area being directly proportional to migratory bird use.

Thesis availability:

Scholarship@Claremont – http://scholarship.claremont.edu/pomona_theses/69/